JP2798135B2 - Compressed image recording / playback system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressed image recording / reproducing system that performs time-division multiplex recording after predictive encoding of a plurality of moving image signals. 2. Description of the Related Art A high-efficiency coding method has been spotlighted for recording a large amount of image data on a recording medium having a relatively small recording capacity. This method is a method in which a prediction value predicted using data of one frame before is subtracted from image data relating to pixels in an XY two-dimensional image plane, and the difference is encoded as prediction error data, thereby compressing the difference. . In general, since the prediction error data can be approximately approximated by a Laplace distribution, in the conventional compressed image recording / reproducing system 1 shown in FIG. 3, a non-linear quantization by logarithmic compression is used as a quantization circuit 3 in an encoder 2 used in a recording system. Circuit is used.
The encoder 2 supplies the input image data to the quantization circuit 3 via a subtractor 4 for calculating a difference from the predicted value. The prediction error data converted from the level value to the level number by the quantization circuit 3 is converted into an unequal-length code by the code conversion circuit 5,
While being recorded on the CD-ROM 6, it is fed back to the subtractor 4 via the local decoder 7. The local decoder 7 supplies the output of an inverse quantization circuit 8 for performing inverse processing of quantization, that is, an inverse quantization circuit 8 for inversely converting a level number to a level value, to a subtractor 4 via a predictor 9, and an input side of the predictor 9. Is positively fed back to the adder 10 provided in the above. On the other hand, a decoder 12 for decoding the prediction error data read from the CD-ROM 6 is a code inverse conversion circuit for returning the prediction error data code-converted by the unequal length encoding to the equal length code by the inverse conversion. 13, an inverse quantization circuit 14 for inversely quantizing the output of the sign inverse transform circuit 13, an adder 15 and a predictor for forming image data from the output prediction error data of the inverse quantization circuit 14.
Consists of sixteen. The output of the inverse quantization circuit 14 is output through an adder 15 and is positively fed back to the adder 15 via a predictor 16, whereby image data is reproduced by cyclic addition of the prediction error data and its decoded output. You. [Problems to be Solved by the Invention] The conventional compressed image recording / reproducing system 1 is a CD-RO
Multiple images can be recorded within the allowable range of the M6 recording capacity, but since these images are recorded in tandem in the order according to the intention of the software maker, the user can select any order. If you try to play back on a CD-ROM, you need to scan over the recording position, and you cannot play back during the scanning period. In the case where the viewing desires of multiple users purchased jointly among the recorded video software are divided, for example, those who wish to play the software with a small total number of applicants will postpone the playback of the desired video software. There is a problem that a case is easily generated. [Means for Solving the Problems] A compressed image recording / reproducing system according to the present invention is a compressed image recording / reproducing system for recording or reproducing a moving image signal that has been predictively coded using a correlation between image units. Prediction error data obtained by predictively encoding a plurality of video signals,
Index data indicating which video signal is related is added to the recording medium, and the data is time-division multiplex-recorded on a recording medium, and the prediction error data recorded in the time-division multiplex is input to first and second input terminals. And outputs the result from an output terminal to a second input terminal of an adder in which a plurality of prediction circuits are selectively connected between the first input terminal and the output terminal, according to the index data. Thus, decoding is performed while switching the prediction circuit, and an output of an arbitrary prediction circuit is used as a reproduction output. [Operation] According to the present invention, an arbitrary moving image signal can be formed by time-division multiplex recording of prediction error data obtained by predictively encoding a plurality of moving image signals using correlation between image units on a recording medium. Reproduction can be performed arbitrarily, and multipurpose use of the image recording medium is aimed at. Embodiment An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a system configuration diagram showing one embodiment of a compressed image recording / reproducing system of the present invention, and FIG.
FIG. 2 is a diagram showing an example of recording data of a CD-ROM shown in FIG. The compressed image recording / reproducing system 21 shown in FIG. ₁ converts a plurality of moving image signals V ₁ , V ₂ ... Vn into the same number of encoders 22 ₁ , 22 as the number of moving images.
₂ .., 22n are individually subjected to inter-frame prediction coding, and prediction error data obtained from these n encoders 22 ₁ , 22 ₂ ... 22n are time-division-multiplexed by a time-division multiplexing circuit 23 with a built-in switch 23a. Multiplexed and recorded on CD-ROM 24.
For this reason, as shown in FIG. 2, a CD-ROM 24 serving as an image recording medium stores prediction errors obtained by individually performing inter-frame prediction coding on n types of image data V ₁ , V _2. Data E ₁
j, E ₂ j .., Enj are time-division multiplex-recorded. The subscript j represents a frame number (1, 2,...), And each prediction error data E ₁ j, E ₂ j .., Enj is related to any image signal. Index data indicating whether or not the index data is added. On the other hand, the prediction error data E ₁ j to
The decoder 25 that decodes Enj has a configuration in which the same number of prediction circuits 26 ₁ , 26 _2, ..., 26 n as the number of recorded moving images are decoded while performing time-division scanning. That is, the prediction circuits 26 ₁ , 26 ₂ ... 26n in the decoder 25 are dedicated to the image signals V _{1 to} Vn, respectively, and input and output before and after these circuits arranged in parallel.
The predictor 27 is configured by connecting the output selection switches 28 and 29. Reference numeral 30 denotes a decoding control circuit that controls the predictor 27, detects index data added to the prediction error data E ₁ j, E ₂ j .., Enj read from the CD-ROM 24, and detects the detected index data. And switches the changeover switches 28 and 29 according to the control. Here, when the prediction error data E ₁ j relating to the j-th frame of the first image signal is supplied to the decoder 25, the decoding control circuit 30 switches the changeover switches 28 and 29 to the prediction circuit 26 ₁
Switch to the side. As a result, the first image signal is to be decoded using the prediction circuit 26 ₁ dedicated sure. Similarly, when the prediction error data Eij relating to the i-th image signal is supplied to the decoder 25, the decoding control circuit 3
0 switches the changeover switches 28 and 29 to the prediction circuit 26i side. Therefore, the i-th image signal is always decoded using the dedicated prediction circuit 26i. Accordingly, the prediction circuits 26 _{1 to} 26 n in the decoder 25 simultaneously reproduce the first to n-th image signals. By the way, in the case of the embodiment, the external output terminals 31 _{1 to} 31 n are connected to each of the prediction circuits 26 _{1 to} 26 n so that their predicted outputs can be supplied to the outside.
By connecting a receiver (not shown) for each of _{1 to} 31n, a plurality of images recorded on the CD-ROM 24 can be simultaneously reproduced using a plurality of receivers. Moreover, even without simultaneous reproduction, for example, if the game software, etc., by switching output according to the judgment or the like of the player the output of the prediction circuit 26 ₁ ~26n, can induce a flow of the game in any situation. In addition, by connecting a changeover switch (not shown) that can be operated externally to the external output terminals 31 _{1 to} 32n, an arbitrary image can be selected from a plurality of images recorded on the CD-ROM 24 and reproduced at the beginning. can do. As described above, the compressed image recording / reproducing system 21
Prediction error data E ₁ j to Enj obtained by predictively encoding a plurality of video signals V _{1 to} Vn using correlation between image units.
The, by CD-ROM 24 time-division multiplex recording, because any video signal V ₁ to Vn is to be able to optionally play, CD
A plurality of multiple video signals V ₁ to Vn was recorded in -ROM24, concurrently it can play, therefore it is easy to reproduce the order of the specified on the part of the user, also was recorded on the same CD-ROM 24 Even if the viewing desires of multiple users are divided among multiple video software, multiple video software can be played at the same time without assigning a playback order. The scene can be changed instantaneously according to the selection will, thereby providing an excellent effect such as the multipurpose use of the CD-ROM 24. Further, the CD-ROM 24 time-division multiplex recording a plurality of video signals V ₁ to Vn that, the exclusive prepared for each video signal prediction circuit 26
_Since decoding is performed while switching between _{1 to} 26n in a time-division manner and reproduced and output with the output of an arbitrary prediction circuit, it is only necessary to prepare prediction circuits 26 _{1 to} 26n according to the number of recorded moving images,
At present, image memories such as field memories or frame memories, which can simultaneously play back multiple moving images and are often used as prediction circuits, can be supplied at low cost due to the mass production effects of semiconductor devices. An inexpensive supply of software and its playback device is possible to the popular game software market. In the above embodiment, the image recording medium is
The magnetic recording medium is not limited to the CD-ROM 24 but may be another magnetic recording medium such as a magnetic disk or a magnetic tape. [Effects of the Invention] As described above, according to the present invention, prediction error data obtained by predictively encoding a plurality of moving image signals using correlation between image units is time-division multiplex-recorded on a recording medium. This allows arbitrary video signals to be reproduced at will, so that a plurality of video signals recorded on a recording medium can be reproduced simultaneously and in parallel, so that the user can easily specify the reproduction order. Yes, it is possible to play multiple video software at the same time without assigning a playback order, even if the viewing desires of multiple users are split among multiple video software recorded on the same CD-ROM. In addition, in the case of game software or the like, it is possible to instantaneously change scenes in accordance with the player's intention to select, thereby achieving excellent effects such as the multipurpose use of an image recording medium. Further, the present invention decodes a plurality of moving image signals time-division multiplex-recorded on the recording medium while switching a dedicated prediction circuit prepared for each moving image signal in a time-division manner, and reproduces and outputs an output of an arbitrary prediction circuit. With this configuration, it is possible to simultaneously reproduce a plurality of moving images only by preparing a prediction circuit corresponding to the number of recorded moving images, and an image memory such as a field memory or a frame memory often used as a prediction circuit is used. At the same time, it is possible to supply the software and its reproducing device at low cost to the popular game software market, especially for young people, which can be supplied at a low cost due to the mass production effect of semiconductor elements.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system configuration diagram showing an embodiment of a compressed image recording / reproducing system according to the present invention, and FIG. 2 is an example of recorded data on a CD-ROM shown in FIG. FIG. 3 is a system configuration diagram showing an example of a conventional compressed image recording / reproducing system. 21: compressed image recording / reproducing system, 22 _{1 to} 22n, 23: time division multiplexing circuit, 24: CD-ROM, 25: decoder, 26 _{1 to} 26n
... Prediction circuit, 30 ... Decoding control circuit.

Continuation of front page       (56) References JP-A-62-191 (JP, A)                 JP-A-57-188187 (JP, A)                 JP-A-61-214882 (JP, A)                 JP-A-58-145284 (JP, A)                 JP-A-54-85631 (JP, A)                 JP-A-52-38811 (JP, A)

Claims (1)

(57) [Claims] A compressed image recording / reproducing system that records or reproduces a moving image signal that is predictively encoded by using a correlation between image units, and predicts and encodes a plurality of moving image signals to obtain prediction error data. Time-division multiplex recording is performed on a recording medium by adding index data indicating whether the data is related to a signal, and the time-division multiplexed prediction error data is added to inputs to first and second input terminals. And a plurality of prediction circuits are selectively connected between the first input terminal and the output terminal, and are supplied to the second input terminal of the adder, and the prediction is performed in accordance with the index data. A compressed image recording / reproducing system characterized in that decoding is performed while switching circuits, and an output of an arbitrary prediction circuit is used as a reproduction output.